At COP21, nations are aiming to finalize a universal agreement on climate change. If successful, this historic meeting will establish the first legally binding universal climate agreement in over 20 years of negotiations, with the aim of keeping global warming below 2°C compared to pre-industrial levels.

This aspiration has its limits. Even if we achieve this target, global warming of 2°C will mean significant changes to our planet. It will lead to more drought, more frequent storms and natural disasters, and greater food and water insecurity.

As we have witnessed with disasters such as Hurricane Sandy in the USA and Typhoon Yolanda in the Philippines, these changes are already happening. Cities and regions around the world are already facing up to the realities of climate change. As a certain level of global warming is already guaranteed, it is vital to act now and to adapt to the coming changes in weather and risk.

Floods and Fires in the USA and Portugal

Boulder, USA has already experienced multiple large-scale disruptive events that have significantly impacted the community and interrupted its role as a service and support center for other affected areas. In 2010 for example, a wildfire began in Fourmile Canyon, requiring the evacuation of nearly 500 homes. Floods in 2013 further illustrated Boulder’s vulnerability when the city’s water and sewer services were seriously jeopardized and came close to going fully off-line.

During these events, even new facilities specifically built to support emergency operations required additional power hook ups, sewer off-takes, communications infrastructure, and food and water management systems to function as support centers. In response, Boulder has begun to develop a program called “Creating District Scale Safe Havens to Support Community Resilience”.

Safe Havens are self-sustaining and self-contained resilience centers that can operate during emergencies. In the long term, Boulder plans to develop a network of Safe Havens; in the short term, it is aiming to bring three pilot installations online by 2020.

The project aims to use existing community facilities, often with significant social value, as rallying points during a crisis. Neighborhoods will be involved in the selection and development of sites, in order to build social cohesion and contribute to community resilience.

Boulder’s project is a simple and straightforward response to a known threat, seeking to guarantee life and property in extreme situations. Almada, Portugal is taking a less orthodox approach to flood prevention and control. Surrounded by water, Almada’s location leaves it highly vulnerable to flash floods, particular following heat waves that dry the soil. Given that the frequency of such events is projected to increase dramatically by 2100, Almada is beginning the long-term process of adaptation.

The city is doing so in a way that brings extensive co-benefits. The project, entitled “MultiAdapt”, involves the construction of four vegetable gardens, including in a water retention basin and the surrounding forested area. The vegetable gardens are designed to absorb the water runoff in the flood plain during storms, serving as a filtration area. As well as helping to reduce the risk of floods, the gardens will mitigate heat waves: evapotranspiration from the vegetation can help to lower the temperature in the nearby urban areas.

In addition, Almada’s citizens will benefit from the vegetable gardens outside of extreme weather events. The vegetation will help to mitigate the urban heat island effect throughout the year, while the vegetable gardens will contribute to Almada’s food security and to the improvement of the urban water cycle.

Landslide Risks in Chile and Brazil

In Recoleta – a commune located in Santiago, Chile – a project with a similar approach has already been implemented. The “Green Terraces” (Terrazas Verdes) initiative was developed as a response to the risks faced by settlements located on the Cerro San Cristobal, the second-highest hill in the city of Santiago. Surveys have indicated a wide area of the hill should not be settled because of risks from landslides and erosion. However, settlements have developed in these areas. Authorities have not removed the settlements but are legally unable to contribute assistance.

Recoleta developed the Green Terraces project, in conjunction with a range of actors including residents associations and nonprofit organizations. After a series of workshops and consultations to inform residents about climate change risks, the community decided to construct a series of containing terraces with stone from the local quarry. Fast-growing plants with large roots have been planted on the terraces to combat soil erosion and to reduce the risk of landslides.

The project was recorded in the form of a publication entitled “Green Terraces: Adaptation to Climate Change through Community Planning and Environmental Education”. The project is an example of community-driven adaptation; by recording and promoting it, the commune hoped to inspire the planning and implementation of other projects centered on citizen participation. This hope was realized: the Green Terraces project prompted a number of projects in the area related to health, urban agriculture on and waste management.

Minas Gerais, Brazil is engaged in a similar project. As in Recoleta, the communities most at risk are the impoverished communities. Their houses are constructed in precarious locations, and the lack of access to sanitation, lighting, education and health exacerbates the communities’ vulnerability to extreme events. Landslides are a threat, particularly during periods of heavy rain.

The city is using the threat of landslides as an opportunity to both increase resilience and raise living standards. Better housing will be provided, along with access to clean water and basic services. To combat the landslide risk in the short term, the city will introduce a series of measures, including the restoration of structurally significant land and the development of paved areas.

The varied approaches of Boulder, Almada, Recoleta and Minas Gerais demonstrate that adaptation measures must be tailored and implemented by local governments. They must be based on the history of the region, the lessons learned from previous incidents and the potential co-benefits. Adaptation measures in developing cities will not necessarily be the same as those in developed cities, and what is transformative in one city may not be so for another.